Dr. Sanjay Singhal
Chief Operating Officer
Stallen South Asia Pvt.
Dr. Kishor Gedam
Product Manager,
Stallen South Asia Pvt. Ltd.
Breathing Trouble: A Glimpse into the World of CRD in Poultry
India ranks second globally in egg production and fifth in poultry meat production. The Indian poultry market, despite being one of the largest globally, remains a developing sector due to its fragmented infrastructure, inconsistent biosecurity standards, and varying degrees of modernization across regions.
A significant portion of poultry production still relies on open housing systems, limited automation, and minimal veterinary oversight, especially among smallholder and backyard farmers. These conditions foster high disease prevalence, as poor sanitation, overcrowding, and lack of structured vaccination programs create ideal environments for the spread of infectious agents like Mycoplasma gallisepticum, E. coli, and coccidia. Consequently, the industry faces substantial economic losses through reduced productivity, higher mortality, increased medication costs, and trade restrictions. Bridging the gap between traditional practices and scientific poultry management is critical for improving flock health and sustaining long-term growth.
One Breath at a Time: Poultry Farmers Battle Chronic Respiratory Disease
Before any effective fight against Chronic Respiratory Disease (CRD) can begin, the poultry industry must first understand the enemy it faces. CRD is not just another seasonal illness—it’s a complex, persistent infection primarily caused by Mycoplasma gallisepticum, capable of silently spreading through flocks and leaving devastating economic consequences in its wake. Its symptoms often mimic those of other respiratory illnesses, making early detection a challenge. Without a clear understanding of its pathogenesis, transmission, and triggers, efforts to control CRD remain reactive and insufficient.
Knowledge is the first line of defense—only with education, diagnosis, and structured prevention can farmers hope to break the cycle of recurring outbreaks. The battle against CRD must begin with awareness and be fought with science, vigilance, and unity across the industry.
Unmasking the Culprit: The Hidden Cause of CRD in Poultry
CRD is caused by Mycoplasma gallisepticum (MG), a wall-less bacterium that affects the respiratory tract of poultry. Secondary infections with Escherichia coli, Ornithobacterium rhinotracheale, and viral pathogens (NDV, IBV) often exacerbate disease severity.
Silent Spread: How CRD Continues to Lurk in Poultry Farms
CRD in poultry, caused by Mycoplasma gallisepticum, spreads through both horizontal and vertical transmission. Infected birds release the pathogen via respiratory secretions, contaminating air, water, feed, and equipment. Vertical transmission from breeder hens to chicks via eggs further fuels early infection. Recovered birds often remain silent carriers, shedding the organism under stress. This makes CRD hard to eradicate and highlights the need for strong biosecurity, breeder screening, and flock management to control its spread.
How CRD Takes Hold: Understanding the Disease’s Journey in Poultry
The pathogenesis of Chronic Respiratory Disease (CRD) in poultry begins when birds inhale aerosolized Mycoplasma gallisepticum, the primary causative agent. The pathogen adheres to the ciliated epithelial cells lining the upper respiratory tract, disrupting the mucociliary clearance mechanism. This allows the bacteria to colonize and multiply, triggering a chronic inflammatory response that leads to thick mucus secretion, tracheitis, and air-sacculitis. The damaged respiratory lining also becomes highly susceptible to secondary bacterial infections, particularly from E. coli, compounding respiratory distress and systemic illness.
In commercial poultry, stress factors such as poor ventilation, high stocking density, and concurrent viral infections (like IBV or NDV) can further exacerbate disease progression, resulting in reduced growth rates, poor feed conversion, decreased egg production, and increased mortality.
Signs & Symptoms with Postmortem (PM) Findings
CRD in poultry typically presents with a range of respiratory signs that can vary in severity based on age, immune status, and presence of co-infections. Common clinical signs include coughing, sneezing, nasal discharge, tracheal rales, conjunctivitis, reduced feed intake, stunted growth, and a noticeable drop in egg production in layers. Birds may also exhibit open-mouth breathing and watery eyes.
In chronic stages, swelling of infraorbital sinuses and air-sacculitis becomes evident. On postmortem examination, the most consistent findings include thickened, cloudy air sacs (airsacculitis), catarrhal to caseous exudate in the trachea and bronchi, perihepatitis, pericarditis, and fibrinous pneumonia. In cases complicated by secondary infections like E. coli, lesions become more severe, showing a classic “CRD complex.”
Integrated Strategy to Fight CRD
An integrated CRD control strategy combines biosecurity, vaccination, early detection, nutritional support, and precision medication.
Preventive Phase: Reducing the Latent Load
Forlutin 10% (Tiamulin 10%) a high-quality feed additive by Stallen South Asia Pvt. Ltd. serves as the cornerstone for preventive management. Administering it to growers between 7 to 14 weeks of age or just before expected stress periods such as vaccination or peak lay helps reduce the latent load of Mycoplasma. This approach prepares the flock by lowering the pathogen load before the birds reach a vulnerable stage.
Outbreak Management: When Clinical Signs Appear
At the onset of clinical signs indicative of Mycoplasmosis, immediate action is required. Stalmicosin (Tilmicosin Phosphate 250mg) oral solution – a high-quality product manufactured by Stallen South Asia Pvt. Ltd. in its own manufacturing facility to ensure the highest Quality standards, administered via drinking water at 15–20 mg/kg body weight, is highly effective due to its deep lung penetration and prolonged action. This should be continued for 3 to 5 days but not exceeded.
Following the Stalmicosin course, a 24–48hour break should be observed before beginning treatment with Forlutin 80% (Tiamulin 80%) water soluble powder. A dosage of 25–50 mg/kg body weight for another 3 to 5 days helps eliminate residual Mycoplasma and prevents recurrence. Integrating these antimicrobials into a scheduled rotation can significantly reduce disease recurrence and resistance development.
Monitoring and Biosecurity: Supporting the Antimicrobial Strategy
Surveillance using PCR and ELISA tests at regular intervals is vital to detect Mycoplasma presence, especially during and after stress periods. Swab sampling and necropsy examinations for lesions such as air sacculitis or swollen joints provide further evidence. Strict biosecurity—enforcing all-in/all-out practices, staff segregation, and regular disinfection using NADCC, quaternary ammonium compounds, or glutaraldehyde—is essential to support the medical interventions.